Siamak Sabour1, Fariba Ghassemi2. 1. Safety Promotion and Injury Prevention Research Center, Shahid Beheshti University of Medical Sciences, Tehran, I.R. Iran; Department of Clinical Epidemiology, Shahid Beheshti University of Medical Sciences, Tehran, I.R. Iran. Electronic address: s.sabour@sbmu.ac.ir. 2. Department of Retina and Vitreous Diseases, Ocular Oncology, Farabi Eye Hospital, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, I.R. Iran.